Collision-Avoidance System and Method for Unmanned Aircraft

ABSTRACT

An obstacle-avoidance system for a vehicle, the obstacle-avoidance system may comprise: a communication device; a plurality of sensors, the plurality of sensors configured to detect collision threats within a predetermined distance of the vehicle; and a processor. The processor may communicatively couple to the communication device and the plurality of sensors and configured to receive navigation commands being communicated to a control system via said communication device. The processor may also receive, from at least one of said plurality of sensors, obstruction data reflecting the position of an obstruction. Using the obstruction data, the processor identifies a direction for avoiding said obstruction. In response, the processor may output, via said communication device, a command to said control system causing the vehicle to travel in said flight direction. Using the obstruction data, the processor may further perform a landing assist module, a three-region collision protection function with pilot override, and/or a target-filtering function.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/863,529, filed Jan. 5, 2018, and titled “Collision-AvoidanceSystem And Method For Unmanned Aircraft,” which claims the benefit under35 U.S.C. § 119(e) of provisional patent application No. 62/443,087,filed Jan. 6, 2017, the contents of which are hereby incorporated byreference.

FIELD

This present disclosure generally relates to autonomous vehiclenavigation and, more specifically, to systems, methods, and techniquesfor detecting and automatically navigating around stationary and/ormoving objects. This present disclosure also relates to sensor- andvehicle-agnostic systems, methods, and techniques for detecting andautomatically navigating around objects.

BACKGROUND

Unmanned aerial vehicle (“UAV”) technology has proven to be a valuabletool for mission profiles involving intelligence, surveillance,reconnaissance, and payload delivery. In contexts such as low-altitudeurban reconnaissance, a UAV, such as a micro-air vehicle (“MAV”), mayencounter both large and small obstacles that may be fixed or moving andwhose position is not known in advance. Moreover, because UAVs and MAVstend to fly in constrained, cluttered environments, they are prone tocrashing or colliding with objects. Furthermore, UAVs and MAVs aregenerally less expensive than traditional aerial vehicles and, as such,are more prevalent and often utilized by less-skilled pilots who may, inturn, cause a collision. Existing technology for preventing UAVs andMAVs from running into objects and other obstacles, such as a GlobalPositioning System (“GPS”), is generally inadequate, as many objectscannot be recognized via a GPS device and, depending on the terrain, GPSaccuracy performance varies widely across environments.

Accordingly, there remains a need for improved autonomous vehiclenavigation systems and obstacle-avoidance systems that can respond tovaried and unknown obstacles in cluttered navigational environments.Furthermore, there is also a need for an autonomous vehicle navigationor obstacle-avoidance system for augmenting and/or overriding navigationcommands communicated to a vehicle.

SUMMARY

An autonomous vehicle may be improved with a flight-control systemhaving a plurality of sensors (e.g., acoustic sensors, visual sensors,or the like). The plurality of sensors may be employed in connectionwith a collision-avoidance solution for small air vehicles, such as thePanoptes™ collision-avoidance system, more generally referred to as adynamic obstacle-avoidance system.

According to a first aspect, a method for providing collision protectionin an aircraft, the method comprises: receiving a sensor input from asensor positioned on the aircraft and operatively coupled with aprocessor, wherein the sensor is configured to identify obstacles withina field of view; receiving a pilot command stream from a pilot;identifying an obstacle within the field of view based at least in parton said sensor input; determining a region from a plurality of regionswithin the field of view in which the obstacle is positioned, whereinthe region is determined based at least in part on the sensor input;setting a control input as a function of the region determined in thedetermining step; inputting the control inputs to aproportional-derivative (PD) controller to generate control data;generating, via the processor, a control command stream as a function ofthe control data; and comparing, via the processor, the control commandstream to the pilot command stream to determine whether the pilotcommand stream from the pilot is safe.

According to a second aspect, a navigation system for providingcollision protection in an aircraft comprises: a sensor configured tocouple to the aircraft and to identify obstacles within a field of view;a processor operatively coupled with the sensor and a memory device,wherein the processor is configured to receive a pilot command streamfrom a pilot, wherein the processor is further configured to: identifyan obstacle within the field of view based at least in part on a sensorinput from said sensor; determine a region from a plurality of regionswithin the field of view in which the obstacle is positioned, whereinthe region is determined based at least in part on the sensor input; seta control input as a function of the region determined in thedetermining step; input the control inputs to a proportional-derivative(PD) controller to generate control data; generate, via the processor, acontrol command stream as a function of the control data; and compare,via the processor, the control command stream to the pilot commandstream to determine whether the pilot command stream from the pilot issafe.

In certain aspects, the control command stream is communicated to aflight controller of the aircraft in lieu of the pilot command streamwhen the pilot command stream from the pilot is determined not to besafe.

In certain aspects, the pilot command stream is communicated to a flightcontroller of the aircraft when the pilot command stream from the pilotis determined to be safe.

In certain aspects, the sensor input comprises a range-rate estimate ora range estimate.

In certain aspects, the pilot command stream is from a human pilot.

In certain aspects, the pilot command stream is from an autopilot.

In certain aspects, the plurality of regions comprises a first region, asecond region, and a third region, such an incoming region, a panicregion, and/or a critical region.

In certain aspects, the first region is defined as an area between asensor maximum range and a first threshold (e.g., an incomingthreshold).

In certain aspects, the second region is defined as an area between thefirst threshold and the second threshold.

In certain aspects, the third region is defined as an area between asecond threshold (e.g., a panic threshold) and the aircraft.

In certain aspects, a pilot command stream is determined not to be safeif the pilot command stream can be interpreted by the processor asattempting to (1) reduce the range between the aircraft and the obstacleor (2) increase the aircraft rate above a rate limit set by the controldata.

In certain aspects, the a pilot override command may be received fromthe pilot, wherein the pilot override command overrides the controlcommand stream.

In certain aspects, the processor is configured to perform atarget-filtering operation.

In certain aspects, the target-filtering operation comprises the stepsof: receiving range and magnitude data from a RADAR system for anobstacle within the aircraft's line of sight; determining, via theprocessor and based at least in part on the range and magnitude data,whether the magnitude is saturated; calculating, via the processor, astandard deviation of at least a portion of a trace reflecting the rangeand magnitude data over time; determining, via the processor, a newrange point for the trace; calculating, via the processor, a minimumdifference between the new range point for the trace and an assignedrange from incoming data; and calculating a confidence and low-passvalue, via the processor, via a critically damped low-pass filter (LPF).

In certain aspects, the confidence and low-pass value is calculatedusing a weighted average of statistical terms derived from a signalmean, a standard deviation, and a magnitude.

In certain aspects, the weighted average is operator-defined for adesired filter performance.

According to a third aspect, a method for providing target-filtering toincrease precision in an aircraft comprises: receiving range andmagnitude data from a RADAR system for an obstacle within the aircraft'sline of sight; determining, via a processor for each of thepredetermined number of obstacles based at least in part on the rangeand magnitude data, whether the magnitude is saturated, wherein theprocessor is configured to set ranges to a known good value if themagnitude is saturated; calculating, via the processor, a standarddeviation of at least a portion of a trace reflecting the range andmagnitude data over time; determining, via the processor, a new rangepoint for the trace; calculating, via the processor, a minimumdifference between the new range point for the trace and an assignedrange from incoming data; determining, via the processor, whether eachof a plurality of conditions are met, wherein the processor isconfigured to calculate a new filtered range point using linearregression if one or more of the plurality of conditions are not met;incrementing an iteration counter; and calculating a confidence andlow-pass value, via the processor, via a critically damped low-passfilter (LPF).

In certain aspects, each of the steps is performed or repeated for eachof a predetermined number of obstacles within the aircraft's line ofsight.

In certain aspects, the predetermined number of obstacles comprises thefive obstacles that are most prominent within the aircraft's line ofsight.

In certain aspects, the standard deviation is of the most recent 20points of the trace through linear regression of the 20 points.

In certain aspects, the minimum difference is a different between thetrace's most recent range and an assigned range from incoming data.

In certain aspects, the plurality of conditions comprises: whether (1)the minimum difference is greater than 3.5 times the standard deviation;and (2) the minimum difference is greater than 0.4.

In certain aspects, the plurality of conditions further comprises:whether (1) the standard deviation is less than 0.2; and (2) theiteration counter is less than 15.

In certain aspects, the confidence and low-pass value is calculatedusing a weighted average of statistical terms derived from a signalmean, a standard deviation, and a magnitude.

In certain aspects, the weighted average is operator-defined for adesired filter performance.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features, and advantages of thedevices, systems, and methods described herein will be apparent from thefollowing description of particular embodiments thereof, as illustratedin the accompanying figures, where like reference numbers refer to likestructures. The figures are not necessarily to scale, emphasis insteadis being placed upon illustrating the principles of the devices,systems, and methods described herein.

FIG. 1 illustrates an environment for autonomous navigation using adynamic collision-avoidance system.

FIG. 2a illustrates a first example autonomous vehicle having a dynamiccollision-avoidance system.

FIG. 2b illustrates a second example autonomous vehicle having a dynamiccollision-avoidance system.

FIG. 2c illustrates an autonomous vehicle having its sensors positionedin a downward facing configuration.

FIG. 2d illustrates an autonomous vehicle having its sensors positionedin a forward facing configuration.

FIG. 2e illustrates an autonomous vehicle having its sensors positionedin both the forward facing configuration and the downward facingconfiguration.

FIG. 3 is a block diagram of a dynamic collision-avoidance andnavigation system for an autonomous vehicle.

FIG. 4 is a flow chart of a method for using a dynamiccollision-avoidance system when navigating a vehicle from a position toan objective.

FIGS. 5a through 5c illustrate an example RADAR flight control/collisionavoidance (RFCA) module.

FIG. 6a is a flow chart of an example three-region collision protectionfunction with pilot override.

FIG. 6b is an illustration of the aircraft vis-á-vis three regions.

FIG. 7 is a flow chart of an example landing assist module.

FIG. 8 is an input and output diagram of an example target filter.

FIG. 9 is a flow chart of an example target-filtering function.

DESCRIPTION

Embodiments of the present disclosure will be described hereinbelow withreference to the accompanying drawings. In the following description,well-known functions or constructions are not described in detailbecause they would obscure the present disclosure in unnecessary detail.Described herein are devices, systems, and methods for autonomousvehicle navigation and, in particular, for navigation using multiplemethods of obstacle avoidance.

All documents mentioned herein are hereby incorporated by reference intheir entirety. References to items in the singular should be understoodto include items in the plural and vice versa, unless explicitly statedotherwise or clear from the context. Grammatical conjunctions areintended to express any and all disjunctive and conjunctive combinationsof conjoined clauses, sentences, words, and the like, unless otherwisestated or clear from the context. Thus, the term “or” should generallybe understood to mean “and/or” and so forth. Recitation of ranges ofvalues herein are not intended to be limiting, referring insteadindividually to any and all values falling within the range, unlessotherwise indicated herein, and each separate value within such a rangeis incorporated into the specification as if it were individuallyrecited herein.

The words “about,” “approximately,” or the like, when accompanying anumerical value, are to be construed as indicating a deviation as wouldbe appreciated by one of ordinary skill in the art to operatesatisfactorily for an intended purpose. Ranges of values and/or numericvalues are provided herein as examples only and do not constitute alimitation on the scope of the described embodiments. The use of any andall examples, or exemplary language (“e.g.,” “such as,” or the like)provided herein, is intended merely to better illuminate the embodimentsand does not pose a limitation on the scope of the embodiments. Nolanguage in the specification should be construed as indicating anyunclaimed element as essential to the practice of the embodiments. Inthe following description, it is understood that terms such as “first,”“second,” “top,” “bottom,” “side,” “front,” “back,” and the like, arewords of convenience and are not to be construed as limiting terms. Forthis application, the following terms and definitions shall apply:

The terms “aerial vehicle” and “aircraft” refer to a machine capable offlight, including, but not limited to, fixed wing aircraft, unmannedaerial vehicle, variable wing aircraft, and vertical take-off andlanding (VTOL) aircraft.

The terms “communicate” and “communicating,” as used herein, refer toboth transmitting, or otherwise conveying, data from a source to adestination and delivering data to a communications medium, system,channel, network, device, wire, cable, fiber, circuit, and/or link to beconveyed to a destination.

The terms “circuits” and “circuitry” refer to physical electroniccomponents (i.e. hardware) and any software and/or firmware (“code”)which may configure the hardware, be executed by the hardware, and orotherwise be associated with the hardware. As used herein, for example,a particular processor and memory may comprise a first “circuit” whenexecuting a first set of one or more lines of code and may comprise asecond “circuit” when executing a second set of one or more lines ofcode.

The term “computer,” as used herein, refers to a programmable devicedesigned to sequentially and automatically carry out a sequence ofarithmetic or logical operations, including without limitation, personalcomputers (e.g., those available from Gateway®, Hewlett-Packard®, IBM®,Sony®, Toshibs®, Dell®, Apple®, Cisco®, Sun®, etc.), handheld,processor-based devices, and any other electronic device equipped with aprocessor or microprocessor.

The term “exemplary” means serving as a non-limiting example, instance,or illustration. Similarly, as utilized herein, the terms “e.g.” and“for example” set off lists of one or more non-limiting examples,instances, or illustrations. As utilized herein, circuitry is “operable”to perform a function whenever the circuitry comprises the necessaryhardware and code (if any is necessary) to perform the function,regardless of whether performance of the function is disabled or notenabled (e.g., by an operator-configurable setting, factory trim, etc.).

The term “processor,” as used herein, refers to processing devices,apparatus, programs, circuits, components, systems, and subsystems,whether implemented in hardware, tangibly embodied software or both, andwhether or not programmable. The term “processor,” as used hereinincludes, but is not limited to, one or more computers, hardwiredcircuits, signal-modifying devices and systems, devices and machines forcontrolling systems, central processing units, programmable devices andsystems, field-programmable gate arrays, application-specific integratedcircuits, systems on a chip, systems comprising discrete elements and/orcircuits, state machines, virtual machines, and data processors.

The term “navigation command,” as used herein, refers to instructionsfor guiding a vehicle. Navigation commands may be represented, orprovided, by a flight-control system as digital or analog datainstructions or signals. Navigation commands may be originated by,without limitation, an autopilot, a pilot (whether locally or remotelysituated), and/or an obstacle-avoidance system. Navigation commands maybe communicated to, for example, a controller or a steering mechanism.

The present disclosure endeavors to provide systems and methods forfacilitating autonomous vehicle navigation and/or obstacle avoidancethrough detection of collision threats. As disclosed herein, autonomousvehicle navigation and/or obstacle avoidance may be facilitated bydetecting one or more collision threats using, inter alia, auditorytechniques (e.g., an echolocation sensor), visual techniques for sensingobjects/obstacles (e.g., non-cooperative targets that are stationaryand/or moving), or a combination thereof. Examples of such collisionthreats may include obstacles such as, without limitation, birds,people, other vehicles, structures (e.g., buildings, gates, towers,etc.), foliage (e.g., trees, bushes, etc.), and the like. Autonomousvehicle navigation and/or obstacle-avoidance functionality (e.g., anyhardware and/or associated methods) may be incorporated with an aerialvehicle's control system (e.g., a flight-control system, whether mannedor autopilot) during its initial design and fabrication; however, suchfunctionality may be alternatively provided through an auxiliary system(e.g., an add-on system, or “retrofit” system) configured to control, oroverride, an existing flight-control system. When auxiliary systems areemployed, it is preferable that they do not require modifications to theexisting flight-control system (e.g., original navigational components)or the aerial vehicle's structure, thereby mitigating unwantedinstallation time and expense, while maintaining any componentwarranties, certifications, etc.

In certain aspects, the autonomous vehicle navigation and/orobstacle-avoidance functionality may be vehicle- and sensor-agnostic.Indeed, for common, small UAVs, overlap exists between the maximumranges of the echo and visual sensors and the closure rates againstfixed obstacles or moving objects where those sensors are effective.Thus, the autonomous vehicle navigation, obstacle- and/orcollision-avoidance functionality may employ echo sensors and/or visualsensors for distance/range measurement. For example, UAVs and MAVs maycomprise sensors including those employing electroacoustic, optical,RADAR, and/or automatic, dependent surveillance-broadcast (“ADS-B”)(e.g., an ADS-B receiver).

Autonomous vehicle navigation and/or an obstacle-avoidance system may besensor-agnostic and process the collected data and fuse the gatheredinformation (i.e., data) received from the various sensors to form aglobal environment estimate. Using the global environment estimate,features relevant to obstacle detection and navigation algorithms, orcollision-avoidance algorithms, may be extracted and stored in adatabase. An algorithm bank may access the database in order todetermine whether action must be taken to avoid a collision upondetection of a collision threat. The algorithm bank may also access thedatabase in order to determine which action must be taken, if one isdeemed necessary.

If an action is necessary, the autonomous vehicle navigation and/orobstacle-avoidance system may then interact with the preexisting vehicleinfrastructure (e.g., an existing flight-control system) to prevent thecollision. Indeed, the interface between the autonomous vehiclenavigation and/or obstacle-avoidance system and an existing system maybe vehicle-agnostic, thereby enabling it to be coupled with a variety ofaerial vehicles, including preexisting aerial vehicles.

FIG. 1 shows an example environment 100 for autonomous navigationemploying the presently disclosed obstacle-avoidance system, which mayalso be generally referred to as a dynamic collision-avoidance system,which may facilitate electronic bumper (“e-bumper”) functionality. Theenvironment 100 may include an objective 102, one or more roads 110 andany number of obstacles such as buildings 112, utility lines 114,utility poles 116, and trees 118. The environment 100 may furthercomprise, in addition, unanticipated obstacles 122 along the path, whichmay be dynamically detected using the dynamic collision-avoidancesystem. As illustrated, an aerial vehicle may be configured to followone or more navigational paths (e.g., navigational paths 104, 106, 108)toward the objective 102, with each path being provided or determinedvia, for example, auto-pilot and configured to address one or moreobstacles.

In accordance with at least one aspect, the aerial vehicle may beconfigured to dynamically avoid the unanticipated obstacles 122 using adynamic collision-avoidance system, whether being guided underautopilot, or by remote control. Specifically, upon detection ofcollision threats (e.g., unanticipated obstacles 122), the dynamiccollision-avoidance system may instruct the aerial vehicle, based onmeasurements received from, for example, a plurality of sensors, tooverride any commands from the autopilot or pilot (e.g., via theflight-control system) to avoid the unanticipated obstacles 122 andultimately return to a navigational path.

FIGS. 2a and 2b illustrate perspective views of a vehicle (e.g., anautonomous vehicle) suitable for use with a dynamic collision-avoidancesystem. The aircraft 200 illustrated in FIG. 2a may comprise an airframe202, landing gear 204, an electronics module 300 (illustrated in FIG.3), and one or more thrust generators 206 (e.g., a turbine, a motor orengine operatively coupled with a propeller, etc.). The electronicsmodule 300 may be integrated with the airframe 202, or provided via aseparate housing or pod. FIG. 2b illustrates a second vehicle that issubstantially the same as the aircraft 200 of FIG. 2a ; however, thesensors 210 of the second vehicle are positioned closer to the center ofthe vehicle and arranged in a separate housing 208. Specifically, whileone may be suitable for certain uses, two or more separate housings 208(e.g., retrofit navigation modules, such the described in connectionwith FIGS. 5a through 5c ) may be positioned around the perimeter of theaircraft 200 to provide a field of view that is oriented with the aerialvehicle's line of flight. The separate housing 208 may be detachablefrom the airframe 202 and may be further configured to house theelectronics module 300, or portion thereof (e.g., functioning as anelectronics module 300 housing). Further, separate housing 208'sfunctionality may be distributed in a suitable manner to not requiremodification to the original navigational components or structurespermanent to the aerial vehicle.

Accordingly, the sensors 210 may be positioned on the aircraft 200 in adownward facing configuration as illustrated in FIG. 2c to detectobstructions below, a forward facing configuration as illustrated inFIG. 2d to detect obstructions ahead of the aircraft 200, or acombination thereof as illustrated in FIG. 2e . As can be appreciated,the sensors 210 may be further positioned on the sides, rear, and/or topof the aircraft 200 to detect obstacles and other threats in alldirections relative to the aircraft 200. Thus, it should be appreciatedthat the sensor 210 location may be determined by the designer as neededfor a particular purpose, sensor type, and/or operation; and thereforeshould not be limited to the layouts depicted in this disclosure. Thelanding gear 204 may be simple skids, as illustrated, or any otherdevice capable of supporting the aircraft 200 when it is not flying,while allowing it to take off, land, and/or taxi without damage, such aswheels, skids, skis, floats, or a combination thereof. The landing gear204 may also be retractable to reduce drag when in flight.

To facilitate controlled flight by adjusting roll, pitch, and yaw of theaircraft 200, the aircraft 200 may further comprise one or more steeringmechanisms 304 or equivalent steering systems configured to receive anavigation command and to respond accordingly. To that end, a steeringmechanism 304 may be operatively coupled with a controller or includeone or more processors, actuators, motors, and/or other devices (e.g.,electrical or electromechanical devices) capable of receiving andresponding to a navigation command. Suitable steering mechanisms 304include, without limitation, traditional flight-control surfaces (e.g.,flaps, ailerons, elevators, rudders, spoilers, air brakes, and/or otherflight-control surfaces), as well as other flight-control mechanisms,such as vectored-thrust control systems. Vectored-thrust controlfunctionality may be facilitated by moving the thrust generators 206 todirect the thrust in a desired direction, thus controlling flight. Forinstance, an articulated, electric motor arrangement may employvectored-thrust control to directly change the thrust vector. Indeed,independently articulating thrust-vectoring motor pods allow rapidtransition between vertical and horizontal flight. In certain aspects,the aircraft 200 may further comprise two or more fins (e.g., verticalstabilizers, and/or horizontal stabilizers), particularly with regard tofixed-wing aerial vehicles.

The aircraft 200 may further comprise an intelligence, surveillance,reconnaissance (“ISR”) payload for gathering data. For example, theaircraft 200 may be equipped with a payload pod comprising one or morecameras, audio devices, and other sensors. Any video, image, audio,telemetry, and/or other sensor data (“Surveillance Data”), collected bythe UAV 106 may be locally stored or wirelessly communicated from theaircraft 200 to a remote location in real time using an antenna coupledwith an onboard wireless communication device, such as atransmitter/receiver. Alternatively, Surveillance Data may becommunicated, or otherwise transferred, to the remote location oranother party via a wired connection (e.g., when tethered, or on theground, post operation).

While the vehicles 200 depicted in FIGS. 2a through 2e arevertical-takeoff-and-landing (“VTOL”) aerial vehicles, it will beunderstood that the autonomous vehicles described herein may include anyvehicle, device, component, element, etc., that may be usefullynavigated using the principles of the dynamic collision-avoidance systemdisclosed herein, including, without limitation, any unmanned vehicle,manned vehicle, aerial vehicle, ground vehicle, aquatic vehicle, spacevehicle, remote-controlled vehicle, large vehicle, small vehicle, and soon, unless explicitly stated otherwise or clear from the text. Forexample, the autonomous vehicles described herein may includehelicopters or other vehicles using horizontal propellers for lift, andso forth. The autonomous vehicles described herein may also, or instead,include aerial vehicles with forward flight capability, such asfixed-wing aerial vehicles. For additional information, other suitableautonomous vehicles are disclosed in greater detail by commonly ownedU.S. Pat. No. 8,500,067, entitled “Modular Miniature Unmanned AircraftWith Vectored-Thrust Control,” and U.S. Patent Publication No.2015/0260526 “Autonomous Vehicle Navigation System And Method.” U.S.Patent Publication No. 2015/0260526, for example, describes an aircraftand sensor payload to provide an improved navigational system thatbenefit from both cameras and echolocation sensors having overlappingfields of view.

Generally, an electronics module may be used to house the vehicle'savionics, power supply (e.g., a propulsion battery, generator, or thelike), sensor payload, and communication device or system. As notedabove, the electronics module may be integrated with the airframe 202 orcontained within a separate housing, which may also potentiallyproviding rigidity to the airframe 202. Thus, the electronics module maybe removable from and replaceable to the airframe 202, and may house anysystems or subsystems of the e-bumper and/or navigation system andmethods as contemplated herein. The electronics module may compriseelectronics and hardware used to support, or facilitate, the e-bumperand navigation system and methods. However, certain electronics and/orhardware may be configured outside of the electronics module housing.For instance, the aircraft 200 may further include one or more sensors210 used to facilitate autonomous flight, which may include, withoutlimitation, echolocation sensors, ultrasonic sensors, infrared sensors,RADAR, and the like. The sensors 210 may be appropriately installed onthe aircraft 200 to enable functionality. For example, placement ofcertain sensors (e.g., those that are vision- or acoustic-based) may beconfigured on the aircraft 200 outside the electronics module housing(if used) because placement of certain sensors within the electronicsmodule housing could hinder or prohibit sensor functionality. Forinstance, as illustrated in FIGS. 2a and 2b , sensors 210 may bepositioned on the surfaces (e.g., top, bottom, edges, etc.) of theairframe 202 and/or atop the electronics module housing (e.g., separatehousing 208).

The sensors 210 may employ one or more echolocation sensors, whichgenerally function by emitting a sound frequency into an environment anddetecting any echoes of the sound frequency that return from obstaclesnear the echolocation sensors. Using the strength of the echo and/ordirection of echo's return, the echoes may be used to locate and/oridentify obstacles, which in turn may cause the aerial vehicle to changedirection to avoid collision with one or more obstacles.

Regardless of the type of sensors 210 employed, the dynamiccollision-avoidance system may be configured to override, or attenuate,commands from a remotely situated pilot when such commands would causethe aircraft 200 to collide with an obstacle. Accordingly, the dynamiccollision-avoidance system provides: (1) attenuation of operator inputsthat would lead to a collision; and (2) if necessary, active reductionof the velocity component in the direction of the object.

To that end, the sensor may be positioned to obtain a field of view inthe vehicle's direction of travel, thereby identifying potentialobstacles in the aircraft 200's path. For example, a single sensor (orsingle group of sensors) may be provided at the front of the vehicle todetect a threat of collision (e.g., obstructions or obstacles) in thepath of the vehicle. Moreover, a plurality of sensors 210 (or multiplegroups of sensors) may be positioned around the perimeter (and/or topand bottom) of the aircraft 200 to provide a field of view that isoriented with the aircraft 200's line of flight. Accordingly, theplurality of sensors 210 would enable the aircraft 200 to detect athreat of collision on any side of the aircraft 200.

As described herein, the sensors 210 may include, inter alfa, anyvision-based sensor or echolocation sensor known in the art or that willbecome known in the art, including, without limitation, ultrasonicsensors and the like. In one aspect, the cameras 206 may be used toidentify larger objects through three-dimensional reconstructiontechniques such as optical flow. While this may provide usefulinformation for autonomous navigation, the processing latency associatedwith optical imaging, as well as the sensitivity to the visibility ofvarious types of objects, may limit the utility of optical sensingtechniques for detecting small, rapidly approaching objects in a line offlight of a vehicle. By orienting the sensors 210 toward the line offlight, acoustic detection may supplement optical detection and be usedfor detecting immediate obstructions that should trigger the executionof responsive maneuvers by a vehicle.

It will be appreciated that one purpose of the acoustic sensors is toprovide immediate detection of obstacles directly in a flight path (orother line of travel), particularly obstacles that might not be detectedusing visual detection or other techniques. Correspondingly, it shouldbe appreciated that one purpose of the sensors 210 is to provideimmediate detection of obstacles in a specific direction (e.g., anydirection of the vehicle), particularly obstacles that might not bereadily detected using visual detection or other techniques. While anecholocation array operates well in this context, other sensor systemsmay also, or instead, be suitably employed for rapid, accurate detectionof obstacles, such as laser-based techniques or any other suitabletechniques using optical, acoustic, radio frequency, or other sensingmodalities. Any such technique suitable for implementation in anautonomous vehicle and capable of accurately and quickly identifyingobstructions may be used in place of the echolocation sensors in thesystems and methods contemplated herein. Thus, the dynamiccollision-avoidance system is generally sensor-agnostic, in that it canbe configured to employ one of a variety of sensor technologies, orcombination thereof. For example, the dynamic collision-avoidance systemmay employ a combination of vision- and acoustic-based sensors.

While the electronics module may be provided as a single housing, theelectronics module may instead comprise multiple housings or“sub-housings.” For example, the electronics module may be divided intotwo housings, a first housing for heavier components, such as thebattery, and a second housing for the more delicate components, such asthe avionics, surveillance payload, sensor payload, and any otherelectronic equipment. The components may be distributed, or dividedamongst housings, to provide a desired weight distribution across theairframe 202.

A flight-control system may be used to control and/or navigate theaircraft 200. The flight-control system need not be a separate physicalitem on the vehicle, but rather may be a component of a largernavigation system or may itself include all of the components of thenavigation system. Unless explicitly stated otherwise or clear from thetext, any components described with reference to the navigation systemmay also be used by or included in the flight-control system and viceversa. In operation, the flight-control system may determine and/orinstruct the aircraft 200 to follow a navigational path in order toreach a desired location based upon signals received from the componentsof the navigation system. For example, the flight-control system mayfacilitate autopilot functionality and/or respond to remote navigationcommands. To that end, the flight-control system 306 may communicativelycouple the aircraft 200 with a remote location, and may be configured tosend and receive signals between (e.g., to and from) the aircraft 200and the remote location. Functionality of the navigational module may bedistributed in any suitable manner between components in theflight-control system, components elsewhere in the aircraft 200, and/orremotely located components. Moreover, a suitable electronic,mechanical, and communication interface may be provided to facilitateremoval and replacement of the electronics module to the airframe 202.

FIG. 3 is a block diagram of an aircraft 200 (e.g., an autonomousvehicle) having a flight-control system 306, a dynamiccollision-avoidance system 302, an electronics module 300, and asteering mechanism 304. More particularly, FIG. 3 illustrates theelectronics module 300 as being used to house, or otherwise contain, thevehicle's flight-control system 306, power supply 336 (e.g., apropulsion battery), sensor payload (e.g., ISR payload 334) andcommunication device(s) 338. However, while a particular arrangement isillustrated in FIG. 3, it will be understood that the arrangement ofcomponents may vary. For example, the flight-control system 306 and/orthe dynamic collision-avoidance system 302 may be located within one ormore dedicated housings and/or removable from the aircraft 200. Forexample, the dynamic collision-avoidance system's functionality may byprovide via a retrofit navigational module removably and non-permanentlycoupled to the vehicle (e.g., via the airframe). Such a retrofitnavigational module may be configured to intercept and modify signals ornavigation commands as disclosed herein.

Alternatively, the flight-control system 306 and/or the dynamiccollision-avoidance system 302 may be integrated into the aircraft 200and coupled in a communicating relationship with the electronics module300 and/or steering mechanism 304. The flight-control system 306 and/orthe dynamic collision-avoidance system 302 may, in certain embodiments,share components, such as memory, sensors, processors, or controllers.Further, the electronics module 300 may be removably coupled to theaircraft 200 or integrated into a fuselage or the like of the aircraft200 in any desired manner. Thus, the arrangement of the variouscomponents may be configured as desired by the designer or operator andtherefore should not be limited to a particular example described orillustrated herein. For example, flight-control system 306 and/ordynamic collision-avoidance system 302 may attach to an exterior of avehicle, or be disposed wholly or partially within the vehicle. Theflight-control system 306 and/or dynamic collision-avoidance system 302may be a removable and replaceable package or a module that is removablefrom and replaceable to the vehicle, or be permanently coupled to orintegrated into the vehicle.

A modular housing may encase one or more components of the electronicsmodule 300, the flight-control system 306, and/or the dynamiccollision-avoidance system 302. The modular housing may be constructedof plastic, metal, wood, a composite material, ceramic, or any materialsuitable for the purposes of a particular vehicle or type of vehicle.The modular housing may be detachable or ejectable, or it may bepermanently coupled to the vehicle. The modular housing may be attachedto the vehicle in any manner known to one of ordinary skill in the art.The modular housing may include openings for sensors such as the sensors210.

Electronics Module 300. As discussed above, the electronics module 300may be used to house the vehicle's 200 avionics (e.g., theflight-control system 206), power supply 336, sensor payload, such as anISR payload 334, and communication device or system 338; and may beintegrated with the airframe 202 or contained within a separate housing.In certain aspects, the electronics module 300 may further comprise thedynamic collision-avoidance system 300, or functionality thereof.

Steering Mechanism 304. The steering mechanism 304 may be configured tosteer the aircraft 200 (whether autonomously or under manned control) ona navigational path to reach an objective as contemplated herein. Theaircraft 200 may be any vehicle referenced herein or otherwise known inthe art (or as will be known in the art). Similarly, the steeringmechanism 304 may be any form of steering referenced herein or otherwiseknown in the art (or as will be known in the art). In general, thesteering mechanism 304 responds to signals from the flight-controlsystem 306, which may employ feedback or other control systems toaccurately direct the aircraft 200 along an intended route.

As noted above, the steering mechanism 304 may include, for example,rudders at the rear of the aircraft 200, as well as elevators, and anyother suitable control surfaces for vertical flight vehicles, along withassociated cables, actuators, and so forth. The steering mechanism 304may also, or instead, include any mechanism for steering an autonomousvehicle. For example, for aerial vehicles, the steering mechanism 304may more generally include rudders, elevators, flaps, ailerons,spoilers, air brakes, and other control surfaces. For other aerialvehicles, such as a helicopter, the steering mechanism 304 may include anumber of rotors, which may be fixed rotors or steerable rotors, alongwith foils and other control surfaces. The steering mechanism 304 mayalso include articulated, electric motors employing vectored-thrustcontrol to directly change the thrust vector. For land-based vehicles,the steering mechanism 304 may include a rack and pinion system,variably rotatable treads, a recirculating ball system, and the like.The steering mechanism 304 may also, or instead, include any componentsto provide thrust, acceleration, and deceleration of the aircraft 200,along with directional control. While vehicles may generally useseparate or integrated components for drive and direction, all suchcombinations that facilitate control over movement of a vehicle areintended to fall within the scope of a “steering mechanism” ascontemplated herein.

Dynamic Collision-Avoidance System 302. The e-bumper module generallyincludes circuitry to facilitate the obstacle-avoidance system'se-bumper functionality. Indeed, the flight-control system 306 and adynamic collision-avoidance system 302 may cooperate to provide anobstacle-avoidance system. As disclosed herein, the dynamiccollision-avoidance system 302 may include one or more sensors 210,where each sensor 210 may have an acoustic field of view (“FOV”).However, the sensors 210 may be any of the echolocation sensorsreferenced herein or otherwise. Using these sensors 210, the dynamiccollision-avoidance system 302 may detect an unanticipated obstacle 122and communicate responsive navigation commands to said flight-controlsystem 306 in order to avoid said unanticipated obstacle 122.

The dynamic collision-avoidance system 302's functionality may befacilitated via flight-control system 306, or an independent system,using a processor 340 (or other comparable logic), memory 342, and oneor more sensors 210 (e.g., acoustic sensors, visual sensors, or acombination thereof) positioned along the top, bottom, and/or perimeter(e.g., one or more edges) of the aircraft 200's airframe 202, asillustrated in, for example, FIGS. 2a and 2b . The dynamiccollision-avoidance system 302 may be used to reduce the likelihood ofcollisions with obstacles in any orientation of the aircraft 200, andfor any relative location of objects to the vehicle. More specifically,a dynamic collision-avoidance system 302 may be provided through aplurality of sensors 210, which may be used to detect various obstacles.In general, the dynamic collision-avoidance system 302 may communicatedirectly with the steering mechanism 304 (or via a controller) and/orwith the flight-control system 306, in order to provide, e.g., senseddata from the sensors 210 and/or derivative commands (e.g., a modifiednavigation command, such as an alternative navigation path, attenuatednavigation signal, or a responsive maneuver, which may be a controlcommand responsive to the sensed data or global environment estimatevalue and configured to avoid an unanticipated obstacle 122).Accordingly, the dynamic collision-avoidance system 302 is particularlyuseful in missions involving operation in close proximity to obstacles.

Certain benefits and contributions of the dynamic collision-avoidancesystem 302 include: (1) the sensor-agnostic method which may be used togenerate the global environment estimate based on individual sensorinputs, (2) the sensor-agnostic method which may be used to interfacewith the existing vehicle control infrastructure in a vehicle-agnosticapproach, and (3) the navigation algorithms necessary to fulfill thee-bumper functionality. For instance, the dynamic collision-avoidancesystem 302 may be integrated into the aircraft 200 and coupled in acommunicating relationship with the steering mechanism 304, theflight-control system 306, an optical system, sensors 210, orcombination thereof.

The dynamic collision-avoidance system 302 is also advantageous in thatit employs a relatively straightforward state machine to activate,scale, or deactivate the influence of each component-operator input,proportional-integral-derivative (“PID”) on distance, autopilotcommands, etc.—in response to the distance from the object, therebyreducing risk of error. Further, a complete state machine estimate canbe assembled with as little as four echolocation sensors. However, incertain embodiments (e.g., when only one direction needs be monitored),an obstacle-avoidance system may be provided using only a single sensorplaced on the front end of the vehicle. Another advantage of the dynamiccollision-avoidance system 302, as disclosed herein, is that the dynamiccollision-avoidance system 302 does not require any cooperative targetsensors. That is, corresponding sensors need not be placed on obstacles,thereby greatly enhancing the utility of the dynamic collision-avoidancesystem 302. Further, the dynamic collision-avoidance system 302 does notrequire aerial vehicle data information or collision-avoidancealgorithms.

A variety of physical configurations are possible and the dynamiccollision-avoidance system 302 may also, or instead, be integrated withthe vehicle 300, the flight-control system 306, or include anycomponents described herein. To that end, as discussed with regard toFIGS. 2a and 2b , sensors 210 may be integrated within the vehicle 300'sshell. Integration of sensors 210 offers a number of advantages. Forexample, the integration of sensors 210 provides a compact package(e.g., in size and weight), while avoiding echolocation sensorinterference (cross talking), as well as/along with avoidingelectromagnetic interference (“EMI”) and propeller acoustic noise.Moreover, the aircraft 200 shell allows for precise placement, low drag,and easy swap of sensors 210 (e.g., if a sensor becomes damaged or if itis otherwise desirable to replace/upgrade the sensor). For example, arecess may be provided within the shell of the vehicle for one or moresensors, thereby mitigating unwanted drag. The sensor may be furthercovered with a protective cover. The protective cover should, however,be configured to not inhibit the sensors' functionality/reliability. Forexample, when acoustic-based sensors are employed, the protective covershould be acoustically invisible (e.g., a fabric or a reflector havingtiny, regularly spaced holes covered by a thin, elastic membrane). Oneexample of an acoustically invisible reflector material is described byJong Jin Park, et al., in the publication entitled, “Giant AcousticConcentration by Extraordinary Transmission in Zero-Mass Metamaterials,”Phys. Rev. Lett. 110, 244302 (published Jun. 13, 2013). Similarly, whenvision-based sensors are employed, the protective cover shouldtransparent or otherwise designed to permit visibility.

Although the current dynamic collision-avoidance system 302 is describedas using echolocation sensors as sensors 210, the dynamiccollision-avoidance system 302 may employ measurements received from anysensor (whether echolocation sensors or another type described herein,without limitation thereto) and fuses the received data to create aglobal environment estimate. From that global environment estimate,features of interest to the algorithms may be extracted and stored in atarget database. The global environment estimate may be an abstractedsummary of what the sensors are detecting around the aircraft. Forexample, if multiple sensors are available that provide a measurement ofthe same state (e.g., range to an obstacle) it fuses those states. Ifmultiple sensors are available that provide multiple distinct states(e.g., range to, and velocity/closure rate of obstacle). Byinstantiating this global environment estimate as an abstracted summaryof the sensed data, as discussed above, it serves as a single interfaceaccessible by the bank of algorithms.

This target database may serve as a common interface for any algorithmthat may be used by the dynamic collision-avoidance system 302 oranother autonomous vehicle navigation or obstacle-avoidance system. Inthe case of the dynamic collision-avoidance system 302, objects that aredetermined to pose a collision threat are passed to the dynamiccollision-avoidance system 302-specific algorithms.

As discussed above, the dynamic collision-avoidance system 302 may beintegrated with the aircraft 200 via a flight-control system 306'svehicle control interface, without modifying the existing systems on theaircraft 200, and without requiring knowledge of the state of thevehicle's autopilot (or manned control). For instance, an embedded logicdevice or processor 340, such as an Arduino© microprocessor, may (1)intercept the original navigation commands (e.g., flight commands by apilot or autopilot), (2) attenuate in accordance with a predeterminede-bumper algorithm, and (3) feed new or modified navigation commands(e.g., attenuated commands generated by the dynamic collision-avoidancesystem) to the vehicle's flight-control system 306 (e.g., autopilot) orsteering mechanism 304 as replacement or override navigation commands.In addition, the dynamic collision-avoidance system 302 may interceptthe control signals (e.g., navigation commands) from the autopilot tothe thrust generators 206 (e.g., an electric motor via pulse-widthmodulation (“PWM”) signals) and modify those signals prior to sendingthem to the flight-control system 306 and/or thrust generators 206(e.g., motors, turbines, etc.). A benefit of the presently discloseddynamic collision-avoidance system 302 is that it achieves the objectiveof obstacle avoidance without requiring alterations to the aircraft200—that is, the dynamic collision-avoidance system 302 isvehicle-agnostic. In certain aspects, because significant delays in thesystem can result in undesirable operation of the aircraft 200, thesoftware implemented on the dynamic collision-avoidance system 302'sembedded device may be constantly monitored for execution speed.

With the global environment estimate and vehicle control interface inplace and tuned, the dynamic collision-avoidance system 302 may focus onnavigation commands (such as those by a pilot or autopilot) that wouldcause the vehicle to crash into an object. The PID distance controllermay also able to hold position and reject unwanted operator input (e.g.,obstacle avoidance). Pilot inputs (e.g., navigation commands) may berejected or modified with high-pass, low-pass, and band-pass filters,feed-forward approaches, and high-gain integrators. In addition,gain-scheduling techniques are implemented for robust controllability.For example, in the case where the vehicle approaches the unanticipatedobstacles 122 due to control inputs by the vehicle's operator, thedynamic collision-avoidance system may reduce the effectiveness of thosecontrol inputs as a function of the distance to the object. If thevehicle continues to approach the unanticipated obstacles 122, thedynamic collision-avoidance system eventually completely attenuates allcontrol inputs in the direction of the object and/or actively reducesthe velocity with which the object is approached. Similarly, if thevehicle is moved toward an object due to environmental conditions (e.g.,winds or gusts) to create a collision hazard, the dynamiccollision-avoidance system provides navigation commands to ensure thatthe vehicle's position does not drop below a predetermined safe distancefrom the object. The attenuation may be adjusted such that the dynamiccollision-avoidance system reduces the effectiveness of those controlinputs (e.g., navigation commands) as a function of the distance to theobject. For example, an inverse distance-attenuation function may beemployed whereby, as the distance between the vehicle and the objectdecreases, the control input attenuation increases such that the controlinputs are effectively decreased, disregarded, or reversed. Further, incertain situations, the dynamic collision-avoidance system can beengaged to maintain the vehicle at a fixed distance from an object toallow that object to be systematically surveyed at close range withoutdanger of influencing the unanticipated obstacles 122. The dual-modecapability of the dynamic collision-avoidance system 302, which includesboth the capability to hold distance relative to object or performobstacle avoidance during flight, makes the dynamic collision-avoidancesystem 302 useful to a wide range of operators. That is, holding adistance between the vehicle and the object is advantageous for datacollection while obstacle avoidance assists inexperienced pilots.

The dynamic collision-avoidance system 302 may further include anarmed/disarmed feature. The armed/disarmed feature may be used, forexample, to prevent the e-bumper controller from erroneously signaling acollision upon detecting the ground during launch or landing. Indeed,the safety measures to arm and disarm the dynamic collision-avoidancesystem 302 at various phases of the flight, takeoff, and landing furtherincrease robustness and safety of the aircraft 200. For example, thedynamic collision-avoidance system 302 may be manually actuated by thecontroller (e.g., a pilot operating the vehicle), or automaticallyarmed/disarmed depending on the distance, position, altitude, flighttime, etc. of the vehicle. In certain aspects, the dynamiccollision-avoidance system 302 may be configured to switch between oneof a plurality of operation modes. The desired operation mode may beselected using, for example, a physical switch positioned on the aerialvehicle, remotely via an operator interface/device (e.g., via a remotecontroller/ground point), or the like. Example operation modes include,without limitation, a disabled mode (i.e., the system is off), aprecision mode, a performance mode, etc. For example, in precision mode,the dynamic collision-avoidance system 302 may enable features such asauto-takeoff, rejection of erroneous operator inputs, obstacleavoidance, precision control of the aircraft through adjusted inputcontrol/aircraft response mapping, etc. Precision mode may also bedesigned to allow the UAV to approach to obstacles closer than inperformance mode (e.g., about 1 to 10 feet, more preferably about 3-7feet, or about 4.5 ft.). In performance mode, the dynamiccollision-avoidance system 302 may provide the same benefits asprecision mode, but be optimized for faster flight regimes. For example,in performance mode, the aircraft may avoid obstacles at a greaterdistance than the performance mode. Additionally, the avoidance maneuvermay be more aggressive than the maneuver in precision mode to protectagainst higher operational velocities.

Flight-Control System 306. The flight-control system 306 may determineone or more navigational paths for the aircraft 200 to reach a desiredlocation based upon signals received from the components of a navigationsystem. The flight-control system 306 may calculate, generate, and sendnavigation commands (e.g., data signals) to the steering mechanism 304to direct the aircraft 200 along a navigational path to the desiredlocation. The flight-control system 306 may be disposed wholly orpartially inside a separate housing, inside the airframe 202, or somecombination thereof. The flight-control system 306 may further includeany of the components of the dynamic collision-avoidance system 302 orflight-control system 306 described, for example, with reference to FIG.3. Indeed, the flight-control system 306 and a dynamiccollision-avoidance system 302 are generally configured to direct, orotherwise control, one or more steering mechanisms 304 within anaircraft 200. The flight-control system 306 may be coupled in acommunicating relationship with the aircraft 200 and a remote locationand may be configured to send and receive signals to and from theaircraft 200 and the remote location via communication device 338.Communication device 338 may be, for instance, a wireless transceiverand antenna.

In general, the flight-control system 306 may include a steering system308, a map system 310, a GPS system 312, a processor 314, a gyroscope316, a controller 318, an accelerometer 320, and/or a memory 330. Theflight-control system 306 may also include the components describedabove as being disposed within the electronics module 300 housing, aswell as other sensors 332, such as any other conventional flightinstrumentation, sensors, processing circuitry, communicationscircuitry, optical system including cameras and the like, necessary oruseful for operation of an unmanned aerial vehicle or other autonomouslyor manually piloted vehicle. One or more of the flight-control system306's components may be housed within the electronics module 300housing.

The flight-control system 306 may be communicatively coupled with theone or more steering mechanisms 304 and/or the dynamiccollision-avoidance system 302. For instance, the steering system 308may be configured to receive signals from the flight-control system 306(or dynamic collision-avoidance system 302) and provide suitable controlsignals to the steering mechanism 304 of the vehicle in order to directthe aircraft 200 along an intended route.

The map system 310 may be part of a map-based flight-control system thatprovides positional information about natural and manmade featureswithin an area. This may include information at any level of detailincluding, e.g., topographical maps, general two-dimensional mapsidentifying roads, buildings, rivers, and the like, or detailed,three-dimensional data characterizing the height and shape of variousnatural and manmade obstructions such as trees, sculptures, utilityinfrastructure, buildings, and so forth. In one aspect, the map system310 may cooperate with an optical system for visual verification ofsurrounding context or the map system 310 may cooperate with the GPSsystem 312 to provide information on various obstacles within anenvironment for purposes of path determination or the like. In oneaspect, the map system 310 may provide a supplemental navigational aidin a GPS-denied or GPS-impaired environment. When GPS is partially orwholly absent, the map system 310 may cooperate with other sensors 332,such as optical sensors, inertial sensors, and so forth to providepositional information until a GPS signal can be recovered.

The map system 310 may more generally communicate with other componentsof the flight-control system 306 in order to support navigation of avehicle as contemplated herein. While this may include providing mapinformation for calculation of routes, this may also include independentnavigational capabilities. For example, the map system 310 may provide amap-based navigation system that stores a map of an operatingenvironment including one or more objects. The map-based navigationsystem may be coupled to cameras and configured to determine a positionof a vehicle by comparing stored objects to a visible environment, whichmay provide position data in the absence of GPS data or other positionalinformation.

The GPS system 312 may be part of a global positioning system configuredto determine a position of the electronics module 300 or the aircraft200. The GPS system 312 may include any GPS technology known in the artor that will become known in the art, including conventional,satellite-based systems as well as other systems using publicly orprivately operated beacons, positional signals, and the like. The GPSsystem 312 may include one or more transceivers that detect data for usein calculating a location. The GPS system 312 may cooperate with theother components of the flight-control system 306 to control operationof the aircraft 200 and navigate the vehicle along an intended path.

The gyroscope 316 may be a device configured to detect rotation of theelectronics module 300 or the aircraft 200 to which the electronicsmodule 300 is coupled. The gyroscope 316 may be integral with theaircraft 200 or it may be disposed inside or outside of the electronicsmodule 300 housing. The gyroscope 316 may include any gyroscope orvariations thereof (e.g., gyrostat, microelectromechanical systems(“MEMS”), fiber-optic gyroscope, vibrating-structure gyroscope,dynamically tuned gyroscope, and the like) known in the art or that willbecome known in the art. The gyroscope 316 may cooperate with the othercomponents of the flight-control system 306 to control operation of theaircraft 200 and navigate the vehicle along an intended path.

The accelerometer 320 may be any device configured to detect a linearmotion of the electronics module 300 or the aircraft 200. Theaccelerometer 320 may be integral with the aircraft 200 or it may bedisposed inside or outside of the electronics module 300 housing. Theaccelerometer 320 may include may include any accelerometer known in theart (e.g., capacitive, resistive, spring-mass base, direct current(“DC”) response, electromechanical servo, laser, magnetic induction,piezoelectric, optical, low frequency, pendulous integrating gyroscopicaccelerometer, resonance, strain gauge, surface acoustic wave, MEMS,thermal, vacuum diode, and the like) or that will become known in theart. The accelerometer 320 may cooperate with the other components ofthe flight-control system 306 to control operation of the aircraft 200and navigate the vehicle along an intended path.

Other sensors (or sensor systems) 332 or sensors 210 may also besimilarly employed. For example, the aircraft 200 (or the flight-controlsystem 306, dynamic collision-avoidance system 302, or electronicsmodule 300 of the vehicle) may employ infrared sensors, RADAR (i.e.,RAdio Detection And Ranging) sensors, LiDAR (i.e., Light Detection andRanging) sensors, and so forth. Any of the foregoing may be used aloneor in combination with other systems and sensors described herein toaugment vehicle navigation. The processor 314 may be coupled in acommunicating relationship with the controller 318, the aircraft 200,the flight-control system 306, the steering mechanism 304, and the othervarious other components, systems, and subsystems described herein. Theprocessor 314 may be an internal processor of the aircraft 200 or theflight-control system 306, an additional processor within theelectronics module 300 to support the various navigational functionscontemplated herein, a processor of a desktop computer or the like,locally or remotely coupled to the aircraft 200, and the flight-controlsystem 306, a server or other processor coupled to the aircraft 200 andthe flight-control system 306 through a data network, or any otherprocessor or processing circuitry. In general, the processor 314 may beconfigured to control operation of the aircraft 200 or theflight-control system 306 and perform various processing and calculationfunctions to support navigation. The processor 314 may include a numberof different processors cooperating to perform the steps describedherein, such as where an internal processor of the aircraft 200 controlsoperation of the aircraft 200 while a processor in the housingpreprocesses optical and echolocation data.

The processor 314 may be configured to determine or revise anavigational path for the aircraft 200 to a location based upon avariety of inputs including, e.g., position information, movementinformation, dynamic collision-avoidance system 302 data, and so forth,which may be variously based on data from the GPS system 312, the mapsystem 310, the gyroscope 316, the accelerometer 320, and any othernavigation inputs, as well as an optical system and the echolocationsystem, which may provide information on obstacles in an environmentaround the aircraft 200. An initial path may be determined, for example,based solely on positional information provided by the GPS system 312,with in-flight adjustments based on movements detected by the gyroscope316, accelerometer 320, and the like. The processor 314 may also beconfigured to utilize an optical navigation system, where the processoris configured to identify a visible obstacle within the FOV of anoptical system; for example, using optical flow to process a sequence ofimages and to preempt the GPS system 312 to navigate the aircraft 200around visible obstacles and toward the location. The processor 314 maybe further configured to identify an obstacle within the FOV of thedynamic collision-avoidance system 302, usually within a line of flightof the vehicle, and further configured to preempt the GPS system 312 andthe optical navigation system to execute a responsive maneuver thatdirects the aircraft 200 around the obstacle and returns the aircraft200 to a previous course toward the location.

The controller 318 may be operable to control components of the aircraft200 and the flight-control system 306, such as the steering mechanism304. The controller 318 may be electrically or otherwise coupled in acommunicating relationship with the processor 314, the aircraft 200, theflight-control system 306, the steering mechanism 304, and the othervarious components of the devices and systems described herein. Thecontroller 318 may include any combination of software and/or processingcircuitry suitable for controlling the various components of theaircraft 200 and the flight-control system 306 described herein,including, without limitation, microprocessors, microcontrollers,application-specific integrated circuits, programmable gate arrays, andany other digital and/or analog components, as well as combinations ofthe foregoing, along with inputs and outputs for communicating controlsignals, drive signals, power signals, sensor signals, and so forth. Inone aspect, this may include circuitry directly and physicallyassociated with the aircraft 200 and the flight-control system 306, suchas an on-board processor. In another aspect, this may be a processor,such as the processor 314 described herein, which may be associated witha personal computer or other computing device coupled to the aircraft200 and the flight-control system 306, e.g., through a wired or wirelessconnection. Similarly, various functions described herein may beallocated among an on-board processor for the aircraft 200, theflight-control system 306, and a separate computer. All such computingdevices and environments are intended to fall within the meaning of theterm “controller” or “processor” as used herein, unless a differentmeaning is explicitly provided or otherwise clear from the context.

The memory 330 may include local memory or a remote storage device thatstores a log of data for the flight-control system 306, including,without limitation, the location of sensed obstacles, maps, images,orientations, speeds, navigational paths, steering specifications, GPScoordinates, sensor readings, and the like. The memory 322 may also, orinstead, store a log of data aggregated from a number of navigations ofa particular vehicle, or data aggregated from a number of navigations ofdifferent vehicles. The memory 322 may also, or instead, store sensordata from an optical system and dynamic collision-avoidance system 302,related metadata, and the like. Data stored in the memory 330 may beaccessed by the processor 314, the controller 318, a remote processingresource, and the like.

FIG. 4 is a flow chart of a method 400 for navigating a vehicle usingthe dynamic collision-avoidance system. The dynamic collision-avoidancesystem starts, or is activated, at step 402. Once activated, the dynamiccollision-avoidance system monitors the environment (e.g., in eachdirection of freedom) using one or more sensors. As discussed above, thesensors may be, for example, echolocation sensors. As shown in step 404,the method 400 may include detecting an unanticipated obstacle 122.

As shown in step 404, the method 400 may include detecting an obstacleusing one or more echolocation sensors (or other suitable sensor). Step404 may include outputting acoustic signals, detecting echoes of thoseacoustic signals, and using the detected echoes to determine the sizeand location of the obstacle. In general, this may be any obstaclecapable of detection through auditory flow that blocks, partiallyblocks, obscures, endangers, etc., the navigational path of the vehiclefrom the position to the objective. The obstacle may be any physicalobstacle such as a building, tree, power line, rock, and so forth. Moregenerally, the first obstacle may be any location or path that thevehicle should avoid.

As shown in step 406, the method 400 may include determining whether toattenuate the navigation commands. The decision as to whether toattenuate the navigation commands at step 412 or to calculate aresponsive maneuver at step 408 may be based upon the distance of theobstacle. For example, if the distance to the obstacle is meets orexceeds a predetermined distance threshold, the dynamiccollision-avoidance system's processor may attenuate the navigationcommands at step 412. If the distance to the obstacle is less than apredetermined distance threshold, thus suggesting a more imminentcollision, the dynamic collision-avoidance system's processor maycalculate responsive maneuver at step 408.

As shown in step 412, the method 400 may include attenuating thenavigation commands. For example, in a case where the vehicle approachesthe obstacles due to control inputs by the vehicle's operator orautopilot, the dynamic collision-avoidance system may adjust the controlinputs based on the distance to the object. If the vehicle continues toapproach the obstacles, the dynamic collision-avoidance system mayeventually completely reject all control inputs in the direction of theobject and/or actively reduce the velocity with which the object isapproached.

As shown in step 414, the method 400 may include calculating aresponsive maneuver that avoids the obstacle. In one aspect, theresponsive maneuver may be a predetermined responsive maneuver thatprovides a temporary excursion from the revised course and returnsimmediately to the revised course after the responsive maneuver has beenexecuted. In another aspect, this may include selecting from among anumber of predetermined responsive maneuvers according to informationabout the obstacle or dynamically creating a responsive maneuveraccording to feedback from the echolocation system. Where appropriate,the responsive maneuver may be further adapted to other data such as GPSdata, optical data, or other sensor data in order to better respond tothe context of the detected obstacle. However calculated, instructionsfor the responsive maneuver may be transmitted to a steering system forthe vehicle for corresponding execution.

As shown in step 410, the method 400 may include determining whether theobstacle is out of range, as a result of the attenuation at step 412 orthe responsive maneuver at step 414. If the obstacle is out of range,the method 400 may end at step 416, or, in the alternative, restart atstep 402 to avoid future obstacles. If the obstacle is still in range,the method 400 may return to step 404.

RADAR Flight Control/Collision Avoidance (RFCA) Module 500. The dynamiccollision-avoidance system 302 may be embodied as a RADAR flightcontrol/collision avoidance (RFCA) module 500 that uses RADAR as one ofthe sensors 210, such as a micro-RADAR sensor with a rectangular beamshaper. As illustrated in FIGS. 5a through 5c , the RFCA module 500 mayinclude a radio-frequency large-scale-integration (RFLSI) component 502,a micro-controller (MCU) 508 coupled with one or more memory devices 504(e.g., RAM and ROM) and one or more of the sensors 210, a cable input506, such as a USB on-the-go connector, and an interface connector 510to the aircraft 200. The RFCA module 500 may further comprise variouselectronic components 512 for signal and voltage handling (e.g.,capacitors, inductors, LDO regulators, etc.). The one of the sensors 210(e.g., micro-RADAR sensor with a rectangular beam shaper) may be locatedon the same PCB 514 or remotely situated and coupled to the PCB 514 viaelectronic conductors or a wireless transceiver.

The interface connector 510 may provide power and universal asynchronousreceiver/transmitter (UART) functionality between the RFCA module 500and the aircraft 200. The RFCA module 500 is preferable compact and, duein part to being vehicle and sensor agnostic, configured to serve as aretrofit that couples with an existing flight control system 306 and/orsteering mechanism(s) 304 of an aircraft 200 via the interface connector510. In operation, sensors 210 provide inputs measurements tomicro-controller 508, which is configured to run one or more softwareprograms (e.g., navigation, altitude hold, landing assist, and collisionprotection software/functions). The micro-controller 508 outputscommands to the flight control system 306 of the aircraft 200. The RFCAmodule 500 is advantageous in that it offers a reliable and flexiblearchitecture that may operate as a single module to capture raw data(e.g., from one or more sensors 210), signal processing, and detectionalgorithms. The data communication between the RFCA module 500 and theaircraft 200 may be facilitated via a single bi-directionalcommunication channel, which may be configurable through, for example, aMAVLink application program interface (API).

The RFCA module 500 may be installed on the aircraft 200 in a downwardfacing configuration, a forward facing configuration, or a combinationthereof. In a downward facing configuration, as illustrated in FIG. 2c ,the RFCA module 500 may facilitate altitude hold and landing assistfunctions (e.g., via a landing assist module). For example, the RFCAmodule 500 may commands the aircraft 200, via the altitude holdfunction, to maintain a predetermined altitude to obstructions detectedbelow (from the ground), or, in the landing assist function, command theaircraft 200 to perform a landing maneuver to avoid an obstructiondetected below. In the forward facing configuration, as illustrated inFIG. 2d , the RFCA module 500 offers collision protection by commandingflight maneuvers in forward direction to prevent collision with adetected obstruction (e.g., serving as a brake). Preliminary testingreveals that the RFCA module 500 offers a range of 1-10 meters, a speedof up to 5 m/s, an update rate at 40 Hz, fields of view (FOV) of 70°(forward facing configuration) and 60° (downward facing configuration),a resolution of 8 cm, with the objects detected being the closestobject, whether stationary or moving.

The RFCA module 500 is preferably compact and lightweight, therebyminimizing the load and imposition on the aircraft 200. For example, anRFCA module 500 may have a length (L) of between 10 mm and 50 mm, morepreferably, between 20 mm and 40 mm, most preferably about 30 mm, whilethe width (W) may be between 10 mm and 40 mm, more preferably, between15 mm and 30 mm, most preferably about 20 mm, with a height (11) between1 mm and 10 mm, more preferably, between 3 mm and 7 mm, most preferablyabout 5 mm. An RFCA module 500 with having 20×30×5 mm, for example, hasshown to have a weight of less than 25 grams and a power consumptionthat is less than 1 watt (W).

Three-Region Collision Protection Function. In certain aspects, theprocessor 340 of the dynamic collision-avoidance system 302 may executea three-region collision protection function with a pilot overridefeature. In certain aspects, however, a separate module includingcircuitry to facilitate the three-region collision protection functionmay be provided. The three-region collision protection function providesa sensor and aircraft agnostic technique for preventing headlongcollision of the aircraft 200 with objects within its environment/range.In other words, the three-region collision protection function providesa “detect and avoid” capability and/or a “sense and avoid” capability toan aircraft 200, which is essential to aircraft navigation, whether viapilot or autonomous flight.

An advantage of an aircraft 200 employing the three-region collisionprotection function (e.g., via the three-region collision protectionalgorithm 600) is the ability to exploit low cost and low fidelity rangemeasurements to provide an effective collision protection system for anaircraft 100 being actively piloted. The three-region collisionprotection function is also able to scale the sensor input from the oneor more sensors 210, while remaining both sensor and aircraft agnosticin its design, thereby enabling the three-region collision protectionfunction to be employed with virtually all aircraft.

An example three-region collision protection function may be facilitatedusing the three-region collision protection algorithm 600 illustrated inFIG. 6a . As illustrated, inputs to the three-region collisionprotection algorithm 600 from one or more sensors 210, a human pilot, oran autopilot are received at step 602. The inputs can include arange-rate estimate, a range estimate, and an input pilot command stream(i.e., pilot commands), which may be a command stream from either ahuman operator or an autopilot. Using these three inputs, thethree-region collision protection algorithm 600 determines, at step 604,a region from a plurality of regions within a physical space in whichthe target is currently positioned. As will be discussed, a region is anarea of space, or portion thereof, that is typically defined by thefield-of-view of the sensors 210 between the vehicle 200 and theoperable range (e.g., maximum operable range) of the sensors 210. Insome embodiments, three regions are identified as: an incoming region622, a critical region 620, or a panic region 618. The three regions maybe identified by using, for example, the formulas provided at step 606.

In other embodiments, as illustrated in FIG. 6b , the three regions maybe identified based on sensor range thresholds (e.g., first and seconddistance thresholds 624, 626) as determined by the operator, whichdictate the distance boundaries. As illustrated, a first region (theincoming region 622) spans the area between the sensor maximum range andthe incoming threshold 626 (e.g., a first threshold/distance), a secondregion (the critical region) spans the area between the incomingthreshold 626 and the panic threshold 624; and a third region (the panicregion 618) spans the area between the panic threshold 624 (e.g., asecond threshold/distance) and the vehicle itself. As can beappreciated, the sensor maximum range may refer to the maximum distanceat which point a given sensor is able to detect objects/targets withreasonable reliability. As illustrated, the shape of each region may bedictated as a function of the shape of the field of view (FOV). Thesensor range thresholds 624, 626 may be received from the operator bythe aircraft 200. For example, if the target is located in either theincoming or the critical region, a rate limit curve is calculated in therange, range-rate domain, using the range thresholds and regionrange-rate limits set by the operator. Based on these determinations,the three-region collision protection algorithm 600 sets the controlinputs (e.g., Rate_(set) and/or K_(p)) in step 606. The three-regioncollision protection algorithm 600 subsequently inputs the Rate_(set)and/or K_(p) control inputs from step 606 to a proportional-derivative(PD) controller at steps 608 to output control data. At step 610, thethree-region collision protection algorithm 600 transforms the controldata (i.e., unit-less, range from −1 to 1) from step 608 to a controlcommand stream (i.e., in pilot command units input from step 602—such asPWM pulse length, range 1000 to 2000). At step 612, the three-regioncollision protection algorithm 600 compares the control command streamfrom step 610 to the pilot command stream (i.e., a pilot command—theinput pilot command stream of step 602) to determine whether the pilotcommand is safe. A pilot command is deemed unsafe if the command can beinterpreted as attempting to reduce the range from the vehicle to thetarget, or increase the vehicle rate above the rate limit (e.g.,Rate_(set)) as set in 606. If the pilot command is determined not to besafe (i.e., unsafe), the three-region collision protection algorithm 600outputs the control command stream from step 610 at step 614. If thepilot command is determined to be safe, the three-region collisionprotection algorithm 600 outputs the input pilot command stream fromstep 602 at step 616.

FIG. 6b illustrates an exemplary embodiment of the three regions, i.e.,panic region 618, critical region 620, and incoming region 622. Theaircraft 200 may have a field of view as shown in FIG. 6b . In thisembodiment, the field of view represents the sensors' field of view upto the sensor max range. The field of view may be divided in to thethree regions based on the operator's threshold inputs, such as thepanic threshold 624 and incoming threshold 626. As such, the control ofthe aircraft 200 may be uniquely restricted as the aircraft 200 enterseach of the three regions. By way of example, the vehicle's 200 maximumspeed, acceleration, and/or the rate limit may be restricted differentlyas the aircraft 200 enters each of the three regions 618, 620, 622. Oncethe aircraft 200 is located in the panic region 618, the system maycontrol the aircraft 200 to slow down. As the aircraft 200 enters thecritical region 620, the aircraft 200 may further slowdown or brake.Finally, when the aircraft 200 is located in the incoming region 622(e.g., the aircraft 200 is in the closest region towards an obstaclewithin its field of view), a braking command may be issued and/or aforward command input by the operator may be ignored to disable anycontrol command to maneuver the aircraft 200 forward. These and othervarious examples of restricting commands/controls would be apparent inview of the subject disclosure to those having ordinary skill in theart.

Landing Assist Module. A landing assist module includes circuitry toautonomously land an aircraft 200 with nominal input from the operatorby automatically controlling the steering mechanism 304 and/or throttleduring a landing operation. In certain aspects, however, the processor340 of the dynamic collision-avoidance system 302 may execute thelanding assist function. The landing assist module benefits from sensorfeedback to prohibit the aircraft 200 from landing on obstructionsand/or in locations that may result in a crash or other hazard to theaircraft 200 (e.g., due to an obstacle). The landing assist module usessensory inputs to close the loop during a landing maneuver to ensure asmooth and safe landing. More specifically, the landing assist moduleemploys inputs from one or more sensors 210 capable of measuring rangeto multiple targets below the aircraft 200. The one or more sensors 210may be, for example, RADAR, LiDAR, stereovision (via two or morecameras), etc.

The landing assist system provides closed loop control and a safelanding check to a flight control system 306 of the aircraft 200 withoutthe need for a beacon or fiducial overseer. By surveying the landingsite (e.g., at the objective 102) and calculating a confidence valuebased on a target filter (described below), the aircraft 200 (via thedynamic collision-avoidance system 302/RFCA module 500/etc.) candetermine whether the area below the aircraft 200 can be used forclosed-loop autonomous landing. In addition to identifying and/orconfirming safe landing zones, the landing assist module can alsogenerate throttle commands and/or control commands for the steeringmechanism 304 to smoothly land the aircraft 200.

The landing assist module maintains safe operation of the aircraft 200through altitude clearance and closed-loop throttle commands. Thelanding assist module measures an altitude of the aircraft 200 throughthe one or more sensors 210 and performs a closed loop throttle controlof the aircraft 200 to provide landing assist. In the event an obstacleis detected (e.g., by an RFCA module 500 in a downward facingconfiguration or another sensors 210), a wave-off operation may beperformed whereby the aircraft 200 aborts its landing and/or identifiesa new landing area. Moreover, range measurements are filtered to firstdetermine the landing target, then to generate a closed loop throttlecontrol/control command, and finally to “wave-off” (e.g., abort) anautonomous land that do not satisfy the landing parameters (e.g.,confidence, max range, and descent rate). The RFCA module 500 maysubsequently identify a new landing zone based on the sensormeasurements, or perform a maneuver other than a hover when the landingzone has been deemed unsafe.

FIG. 7 illustrates an example landing assist flow chart 700 for alanding assist function of a landing assist module. As illustrated,inputs to the landing assist module are received at step 702. The inputscan include a range array and landing parameters, which may be generatedby either a human operator or an autopilot.

At step 704, a landing target filter determines the number of targetsfrom range array. At step 706, the landing assist module determineswhether the number of targets is greater than one. If the number oftargets is greater than one, the landing assist module proceeds to step708, otherwise the landing assist module proceeds to step 710. At step708, the landing assist module sets the target to equalMinimum(Range_Array) and proceeds to step 710. At step 710, the landingassist module determines whether the target satisfies the landingparameters. If the target satisfies the landing parameters, the landingassist module proceeds to step 712, otherwise the landing assist moduleproceeds to step 716. At step 712, the landing assist module setsLand_State to equal False and proceeds to step 714. At step 714, thelanding assist module outputs, for example, Land_State to the flightcontrol system 306. At step 716, the landing assist module setsLand_State to equal True and proceeds to step 718. At step 718, thelanding assist module employs proportional-integral-derivative (PID)controller to general a control signal and proceeds to step 720. At step720, the landing assist module transforms the control signal from step718 to a Throttle_Cmd units. At step 722, the landing assist moduleoutputs, for example, Land_State and Throttle_Cmd from step 720 to theflight control system 306. The vehicle flight control system can thenquery the Land_State to take appropriate action and apply theThrottle_Cmd to the appropriate control loop.

A default output from the landing assist module may include, forexample: Altitude_Clearance, Pilot_Thrust_Command, and Land_State. Theoutput may, however, be customized to meet a particular need. A customoutput may include, for example: Altitude_Relative, Target_VZ (velocityin z-direction). The parameters of the landing assist module can beconfigured through API.

Target-filtering Module. A problem with RADAR sensors is that the outputis typically scattered and chaotic data due to the RADAR sensor'sability to detect objects over a large area. Consequently, construingthe data returned from the RADAR sensor can be difficult, especially fornavigational decision processes. In operation, a RADAR sensor maymeasures the five most prominent objects within its line of sight tooutput both the relative distance of the object and the magnitude atwhich the RADAR is detecting. These values are typically output in orderof descending magnitudes, but this method of feedback is inadequate forcollision avoidance and autonomous flight because, in a dynamicenvironment, obstructions are continuously surpassing each other inmagnitude (as seen by the RADAR) and reported distances areinterchanged; thus, causing large jumps in feedback that severelyimpacts closed loop controllers.

A solution is to employ a target-filtering module including circuitry toimplements a target-filtering algorithm to detect real objects versusnoise, and to track the objects such that clean feedback signals arereturned to the aircraft 200. The target-filtering module implements atarget-filtering algorithm to prevent jumps, smooth the output, andreport a confidence value, which can be used to prevent false-positivesof a collision avoidance system. Target-filtering and optimization of afive range, five magnitude RADAR unit, therefore, allows for theidentification and tracking of obstruction using data obtained from aRADAR sensor. The target-filtering module may therefore providefiltering and optimization of a five range, five magnitude RADAR sensorpayload for an aircraft 200 to address this problem by enabling thetracking of five objects simultaneously.

The capability to perform object tracking enhances both autonomousnavigation and collision avoidance. In certain aspects, the processor340 of the dynamic collision-avoidance system 302 may execute thedisclosed target-filtering function. Therefore, a target-filteringmodule converts unstable and noisy RADAR measurements into a cleansignal capable of being utilized for collision avoidance as well asautonomous flight feedback. The target-filtering module emphasizes thestrengths of the RADAR module, while attenuating its drawbacks tooptimize performance for the aircraft 200. Similar solutions can bederived by minor altercations of the current algorithm. There is someflexibility in the choice of sub-functions (i.e. types of digitalfilters, linear vs. polynomial curve fitting, Gaussian vs. Binomialestimated distributions, etc.).

FIG. 8 illustrates an input and output diagram 800 of an example targetfilter module, which includes circuitry to combines sensory data fromone or more sensors 210 to generate filtered ranges with correspondingconfidence values using a target filter algorithm 812. The one or moresensors 210 may include a RADAR and altimeter to collect altitudemeasurements 802, RADAR magnitude 804, and RADAR range 806. Using signalproperty extraction techniques 810, the target filter algorithm 812 maydetect outlier measurements from the RADAR to eliminate faulty datapoints. Range assignments and confidence values are calculated usingweighted averages of signal properties, RADAR magnitudes, and estimatesof ground noise.

FIG. 9 illustrates an example flow chart 900 for providing atarget-filtering functionality using a target-filtering module, wherethe Std_Dev is the standard deviation of the most recent 20 points of atrace through linear regression of these 20 points. The Min_Diff is theminimum difference between a trace's most recent range and the assignedrange from the incoming data. The Iteration_Counter (Iteration Count orCounter) is the number of consecutive extrapolations. Finally, theConfidence Value is the confidence of a range being a real target, whichis calculated using the weighted sums of Magnitude and Std_Dev.

At step 902, the target-filtering module receives the first of five newranges and magnitude from RADAR for the five most prominent objectswithin the line of sight, and then proceeds to step 904. At step 904,the target-filtering module determines whether the magnitude issaturated. If the magnitude is saturated at step 904, thetarget-filtering module sets ranges to a previously known good value atstep 906 and continues at step 908. If the magnitude is not saturated atstep 904, the target-filtering module continues to step 908. At step908, the target-filtering module calculates the Std_Dev and proceeds tostep 910. At step 910, the target-filtering module calculates and/oridentified the new range point that is best fitting for the currenttrace and proceeds to step 912. At step 912, the target-filtering modulecalculates the Min_Diff and proceeds to step 914. At step 914, thetarget-filtering module determines whether four conditions are met, thefour conditions being: whether (1) the Min_Diff is greater than 3.5times the Std_Dev; (2) Min_Diff is greater than 0.4; (3) Std_Dev is lessthan 0.2; and (4) Iteration_Counter is less than 15. If each the fourconditions is met at step 914, the target-filtering module proceeds tostep 916; otherwise the target-filtering module proceeds to step 920.

At step 916, the target-filtering module calculates new filtered rangepoint using linear regression and proceeds to step 918. At step 918, thetarget-filtering module increments the Iteration_Counter and proceeds tostep 924.

At step 920, the target-filtering module assigns an optimum data pointfrom the RADAR to filter the output range and proceeds to step 922. Atstep 922, the target-filtering module removes assigned ranges frompotentially being used in traces and proceeds to step 924.

At step 924, the target-filtering module calculates confidence andlow-pass using critically damped low-pass filter (LPF) and proceeds tostep 926. The confidence and low-pass values may be calculated using aweighted average of statistical terms derived from the input rangesignal (e.g., signal mean, standard deviation, and magnitude). Theweighting of the terms in the confidence calculation can be determinedby the operator (i.e., operator-defined) and tuned for desired filterperformance (e.g., by the operator). At step 926, the target-filteringmodule repeats the forgoing (starting at step 902) for each of ranges2-5 and, when all of ranges 1-5 are complete, proceeds to step 928. Atstep 928, the target-filtering module returns filtered range andconfidence values.

In some embodiments, the confidence and low-pass values may bedetermined based on an environment in which the aircraft 200 is commonlyoperated. For example, in an operating environment where snow is common,the reflectivity of the snow may be considered a common cause of thelevel of noise being detected. As such, the system may set theconfidence and/or low-pass values accordingly to adjust the acceptablenoise level detected by the RADAR. Similarly, a machine learningalgorithm may be applied with the target-filtering functionality of thepresently described system.

The systems described herein may also include client devices, which mayinclude any devices operated by operators to initiate, manage, monitor,control, or otherwise interact with the navigation system or autonomousvehicle. This may include desktop computers, laptop computers, networkcomputers, tablets, or any other computing device that can participatein the systems as contemplated herein. The client devices may include anoperator interface, which may include a graphical user interface (GUI)as the operator interface, a text or command line interface, avoice-controlled interface, and/or a gesture-based interface to controloperation of the navigation system or autonomous vehicle. The operatorinterface may be maintained by a locally executing application on one ofthe client devices that receives data and status information from, e.g.,the navigation system or autonomous vehicle. The operator interface maycreate a suitable display on the client device for operator interaction.For example, the operator interface may include a display that displays,in real time, views from the cameras in the optical system, or displaysother data from other sensors within the navigation system. In otherembodiments, the operator interface may be remotely served and presentedon one of the client devices. For example, where the navigation systemor autonomous vehicle includes a web server that provides informationthrough one or more web pages or the like that can be displayed within aweb browser or similar client executing on one of the client devices. Inone aspect, the operator interface may include a voice-controlledinterface that receives spoken commands from an operator and/or providesspoken feedback to the operator.

While the above systems are primarily described as being applied toaerial vehicles, one of skill in the art would understand that suchsystems, methods, and techniques might be employed with othertechnologies, such as automotive, warehouse equipment, constructionequipment, cranes, powered wheel chairs, airport equipment, etc.

The above systems, devices, methods, processes, and the like may berealized in hardware, software, or any combination of these suitable forthe control, data acquisition, and data processing described herein.This includes realization in one or more microprocessors,microcontrollers, embedded microcontrollers, programmable digital signalprocessors, or other programmable devices or processing circuitry, alongwith internal and/or external memory. This may also, or instead, includeone or more application-specific integrated circuits, programmable gatearrays, programmable array logic components, or any other device ordevices that may be configured to process electronic signals. It willfurther be appreciated that a realization of the processes or devicesdescribed above may include computer-executable code, created using astructured programming language such as C, an object-orientedprogramming language such as C++, or any other high-level or low-levelprogramming language (including assembly languages, hardware descriptionlanguages, and database programming languages and technologies) that maybe stored, compiled, or interpreted to run on one of the above devices,as well as heterogeneous combinations of processors, processorarchitectures, or combinations of different hardware and software. Atthe same time, processing may be distributed across devices, such as thevarious systems described above, or all of the functionality may beintegrated into a dedicated, standalone device. All such permutationsand combinations are intended to fall within the scope of the presentdisclosure.

Embodiments disclosed herein may include computer program productscomprising computer-executable code or computer-usable code that, whenexecuted on one or more computing devices, performs any and/or all ofthe steps of the control systems described above. The code may be storedin a non-transitory fashion in a computer memory, which may be a memoryfrom which the program executes (such as random access memory associatedwith a processor) or a storage device such as a disk drive, flashmemory, or any other optical, electromagnetic, magnetic, infrared, orother device or combination of devices. In another aspect, any of thesystems and methods described above may be embodied in any suitabletransmission or propagation medium carrying computer-executable codeand/or any inputs or outputs from it.

The method steps of the implementations described herein are intended toinclude any suitable method of causing one or more other parties orentities to perform the steps, consistent with the patentability of thefollowing claims, unless a different meaning is expressly provided orotherwise clear from the context. Such parties or entities need not beunder the direction or control of any other party or entity and need notbe located within a particular jurisdiction.

Any patents, patent publications, or articles cited herein are herebyincorporated by reference in their entirety. It will be appreciated thatthe methods and systems described above are set forth by way of exampleand not of limitation. Numerous variations, additions, omissions, andother modifications will be apparent to one of ordinary skill in theart. In addition, the order or presentation of method steps in thedescription above and attached drawings is not intended to require thisorder of performing the recited steps unless a particular order isexpressly required or otherwise clear from the context. Thus, whileparticular embodiments have been shown and described, it will beapparent to those skilled in the art that various changes andmodifications in form and details may be made therein without departingfrom the spirit and scope of this disclosure and are intended to form apart of the invention as defined by the following claims, which are tobe interpreted in the broadest sense allowable by law.

What is claimed is:
 1. A method for performing a target-filteringoperation in an aircraft, the method comprising: receiving range andmagnitude data from a RADAR system for an obstacle within a line ofsight of the aircraft; determining, via a processor and based at leastin part on the range and magnitude data, whether the magnitude issaturated; calculating, via the processor, a standard deviation of atleast a portion of a trace reflecting the range and magnitude data overtime; determining, via the processor, a new range point for the trace;calculating, via the processor, a minimum difference between the newrange point for the trace and an assigned range from incoming data; andcalculating, via the processor, a confidence and low-pass value using acritically damped low-pass filter (LPF).
 2. The method of claim 1,wherein each step of claim 1 is performed for each of a predeterminednumber of obstacles within a line of sight of the aircraft.
 3. Themethod of claim 2, wherein the predetermined number of obstaclescomprises five obstacles within the line of sight that are determined tobe most prominent.
 4. The method of claim 1, wherein the standarddeviation is of most recent 20 points of the trace through linearregression of the most recent 20 points.
 5. The method of claim 1,wherein the minimum difference is a different between a most recentrange of the trace and an assigned range from incoming data.
 6. Themethod of claim 1, wherein the confidence and low-pass value iscalculated using a weighted average of statistical terms derived from asignal mean, a standard deviation, and a magnitude.
 7. The method ofclaim 6, wherein the weighted average is operator-defined for a desiredfilter performance.
 8. The method of claim 1, further comprising thestep of determining, via the processor, whether each of a plurality ofconditions are met, wherein the processor is configured to calculate anew filtered range point using linear regression if one or more of theplurality of conditions are not met; and incrementing an iterationcounter.
 9. The method of claim 8, wherein the plurality of conditionscomprises: whether (1) the minimum difference is greater than 3.5 timesthe standard deviation; and (2) the minimum difference is greater than0.4.
 10. The method of claim 8, wherein the plurality of conditionsfurther comprises: whether (1) the standard deviation is less than 0.2;and (2) the iteration counter is less than
 15. 11. A system forperforming a target-filtering operation in an aircraft, the systemcomprising a processor operatively coupled with a RADAR system and amemory device, wherein the processor is further configured to: receiverange and magnitude data from the RADAR system for an obstacle within aline of sight of the aircraft; determine, based at least in part on therange and magnitude data, whether the magnitude is saturated; calculatea standard deviation of at least a portion of a trace reflecting therange and magnitude data over time; determine a new range point for thetrace; calculate a minimum difference between the new range point forthe trace and an assigned range from incoming data; and calculate aconfidence and low-pass value via a critically damped low-pass filter(LPF).
 12. A navigation system for providing an aircraft with collisionprotection, the navigation system comprising: a sensor configured tocouple to the aircraft and to identify obstacles within a field of view;a processor operatively coupled with the sensor and a memory device,wherein the processor is configured to: receive a first command stream;identify an obstacle within the field of view based at least in part ona sensor input from said sensor; determine a region from a plurality ofregions within the field of view in which the obstacle is positioned,wherein the region is determined based at least in part on the sensorinput; set a control input as a function of the region determined fromthe plurality of regions; generate, via the processor, a second commandstream as a function of control data, wherein the control data isgenerated based at least in part on the control inputs; and compare, viathe processor, the second command stream to the first command stream todetermine whether the first command stream is safe.
 13. The navigationsystem of claim 12, wherein the control data is generated using aproportional-integral-derivative (PID) controller.
 14. The navigationsystem of claim 12, wherein the second command stream is communicated toa flight controller of the aircraft in lieu of the first command streamwhen the first command stream is determined not to be safe.
 15. Thenavigation system of claim 12, wherein the plurality of regionscomprises a first region, a second region, and a third region.
 16. Thenavigation system of claim 12, wherein a first command stream isdetermined not to be safe if the first command stream can be interpretedby the processor as attempting to (1) reduce a range between theaircraft and the obstacle or (2) increase a rate of the aircraft above arate limit set by the control data.
 17. The navigation system of claim12, wherein the first command stream is from a pilot of the aircraft.18. The navigation system of claim 17, wherein the processor isconfigured to receive a pilot override command from the pilot thatoverrides the second command stream.
 19. The navigation system of claim12, further comprising a landing assist module to instruct the aircraftto perform a landing maneuver to avoid an obstruction detected below theaircraft.
 20. The navigation system of claim 12, wherein the processoris configured to perform a target-filtering operation that comprises thesteps of: receiving range and magnitude data from a RADAR system for anobstacle within a line of sight of the aircraft; determining, based atleast in part on the range and magnitude data, whether the magnitude issaturated; calculating a standard deviation of at least a portion of atrace reflecting the range and magnitude data over time; determining anew range point for the trace; calculating a minimum difference betweenthe new range point for the trace and an assigned range from incomingdata; and calculating a confidence and low-pass value using a criticallydamped low-pass filter (LPF).